1. Field of the Invention
The present invention relates generally to compositions and methods for inhibiting replication of human immunodeficiency virus (HIV)-1. More particularly, the present invention provides polypeptide compositions which interfere with binding between the Rev protein and Rev-responsive element (RRE) of HIV-1, which binding is essential for HIV-1 replication.
The Rev protein of HIV-1 is a gene regulatory protein that is essential for viral replication. Although the exact function of Rev is not understood, it is known that it is essential to facilitate transport of unspliced vital mRNA from the cell nucleus to the cytoplasm. The unspliced mRNA is then translated into viral structural proteins which are assembled into infectious viral particles. The Rev protein must bind to a site within the mRNA, referred to as the IIB site of the Rev-responsive element (RRE), which is a stem-loop structure containing an asymmetric internal budge and at least one non-Watson-Crick base pair. It has been previously shown that a synthetic peptide including amino acids 34-50 of the Rev protein is sufficient for specific binding to the IIB site.
As binding between the Rev protein and the RRE is essential for HIV-1 replication, it would be desirable to identify and provide compositions capable of blocking or interfering with such binding in order to prevent or inhibit such replication. In particular, it would be desirable to provide compositions which are able to specifically bind to the IIB site of the RRE but which will not provide the essential Rev protein function. Desirably, such compounds will bind to the RRE in preference to native Rev protein, displaying a greater affinity and/or specificity for the IIB binding site than the native protein. Such compositions should be stable and suitable for incorporation into pharmaceutical products for administration to humans. It would be further desirable to provide in vitro and in vivo methods for screening test compounds to identify those compounds which are able to effectively compete with native Rev protein for binding to the RRE, which test compounds would be suitable for further screening for effectiveness as therapeutic agents for the treatment of HIV-1 infection.
2. Description of the Background Art
Binding between the Rev gene product and the Rev-responsive element (RRE) in HIV is described in Heaphy et al. (1991) Proc. Natl. Acad. Sci. USA 88:7366-7370; Bartel et al. (1992) Proc. Natl. Acad. Sci. USA 89:758-762. Binding between a 17 amino acid peptide corresponding to residues 34-50 of Rev was shown in Kjems et al. (1991) Cell 67:169-178 and (1992) EMBO J. 11:1119-1129. Inhibition of binding between Rev and RRE as a therapy for HIV-1 infection is proposed in, e.g., Rosen (1992) J. Virol. 66:600-607. Therapeutic strategies for HIV-1 infection are proposed in the following published PCT patent applications: W092/07871; W092/05195; and W091/10453. The expression of the Rev protein of HIV-1 in Drosophila cells is described in W092/06212.